I might stop the general weekly round-ups now, since I’m back on my feet after surgery and therefore have no need to update people via the blog. But the reading will continue, obviously, and so will the book round-ups.

Numerosity is the concept of someone being able to look at a group of items and determine the rough size of each. Presented with two pictures, one with five dots and one with five hundred, for example, they should be able to comprehend the five hundred dot image as more numerous than the five dot image.

This is a quality possessed by many animals, from apes to invertebrates. It makes sense for this to be the case: if you’re a sardine, you’re going to want to be able to differentiate between a group of five other sardines, and an entire shoal. This has certain evolutionary advantages, not least because many animals group together for safety.